By Kim Hyun-binBitter cold weather triggered an unexpected electricity hike across the country, putting the country's power supply at risk. On Thursday, the Korea Power Exchange (KPX) ordered its client companies to reduce electricity consumption between 9 a.m. and 11:30 a.m., after national power consumption rose to 86 million kilowatts earlier in the morning, abnormally high compared to previous winters.It marked the fourth order by the KPX this year. The KPX issues an electricity reduction order when load reductions are needed to prevent shortfalls in the power supply. It issued five such orders last year.Adopted in 2014, 3,580 companies are members of the system, 2,736 of which took part in the government's efforts to save electricity Thursday. "About 2,700 companies could save around 2.7 million kilowatts of electricity during peak hours," the KPX said.The weather agency issued a cold weather alert across the country with temperatures dropping to minus 17 degrees Celsius in the capital on Thursday. Electricity demand hit an all-time high Wednesday with 86.2 million kilowatts and the reserve rate at 14.2 percent. The government's forecast for peak electricity was 85.2 million kilowatts.The cold wave is likely to continue Friday with Seoul's temperature forecast to fall to minus 15 degrees Celsius. "It is most likely the KPX could issue another order Friday," a KPX official said.Public concerns is growing over a possible power outage.